Gearbox tars have architecture in build name/file name

@evansde77 @turtlebender @waltaskew @msmathers 

Hey guys,

At least three of us have been bitten by the silly mistake of doing a build on our laptops and then expecting that code to run on an ubuntu machine.  

Dave and I talked about it this morning and agreed that having the build architecture specified in the gearbox tarball filename would be helpful.